1. Field of the Invention
The present invention relates to a digital image processing system.
2. Description of the Prior Art
An image processing system such as a digital copier or a facsimile system has been recently proposed. Such an apparatus has an accumulating transducer element such as a solid-state image pick-up device, e.g., a CCD for reading an image and converting an analog signal into a digital signal. The obtained digital signal is processed and is transmitted through a digital transmission line or is used to reproduce an image by a laser beam printer or the like.
In order to transmit and accumulate image signals, a digital image processing apparatus of this type requires a special processor, transmitter and storage.
This requires image processing equipment in addition to other image processing equipment forward processing or computer processing. Such an increase in the amount of hardware results in reduced space in the office using equipment of this type, difficult handling, and an increase in the cost.
A method is conventionally known for compressing and expanding digital image data so as to reduce the amount of data transmitted.
However, in a digital recording apparatus, due to the requirements in of high-speed and a high-quality image together with an increase in the amount of data to be handled, high speed image signal processing must be performed. However, it is technically difficult to compress, expand and transmit read digital image signals in real time.
Furthermore, depending upon a particular pattern arrangement, the amount of image data may be increased upon data compression. For example, in the Modified Huffman one-dimentional run length coding method, 2-bit data of 1 black bit and 1 white bit is converted into 9-bit data upon coding. This increase in the amount of data may exceed the transfer capacity of a transmission line or occupying time of the line.
When the pel density or image processing speed is different between an image reader and an image recorder, connection of the image reader with the image recorder for exchange of the digital image data is either very difficult or impossible.